Enable image capture under Cygwin

![1d29a513e3f](https://f.cloud.github.com/assets/115420/609170/45506df6-cd77-11e2-9354-2f7b8879d118.jpg)

Had to tweak things to get capture working. I doubt I did things the proper way since I'm not a Ruby guy, but figured I'd show my work to prompt discussion.

As an aside, is the commit message being cut off because my webcam is super low-res? Or something else?